Drosophila meridionalis is a cactus-breeding species with a wide distribution in South America. Most populations of this species are geographically isolated, what provides a promising scenario for studying evolution. Former studies of this species revealed a remarkable karyotypic variation among its populations. Up to six distinct metaphase chromosomes were described, showing that this species ...

Alignment of the mitotic spindle along a preformed axis of polarity is crucial for generating cell diversity in many organisms, yet little is known about the role of the endomembrane system in this process. RAB-11 is a small GTPase enriched in recycling endosomes. When we depleted RAB-11 by RNAi in Caenorhabditis elegans, the spindle of the one-cell embryo failed to align along the axis of pola...

In the article we summarize the most common recent cytogenetic methods used in analysis of karyotypes in Heteroptera. We seek to show the pros and cons of the spreading method compared with the traditional squashing method. We discuss the suitability of gonad, midgut and embryo tissue in Cimex lectularius Linnaeus, 1758 chromosome research and production of figures of whole mitosis and meiosis,...

At anaphase, the linkage betweeh sister chromatids is dissolved and the separated sisters move toward opposite poles of the spindle. We developed a method to purify metaphase and anaphase chromosomes from frog egg extracts and identified proteins that leave chromosomes at anaphase using a new form of expression screening. This approach identified Xkid, a Xenopus homolog of human Kid (kinesin-li...

Mitosis and male meiosis were studied in Myrmedobia coleoptrata (Fn.), (Heteroptera, Microphysidae). Spermatogonial metaphase revealed 14 chromosomes (2n=12 + XY). The nucleolar organizing region was found on the X chromosome. No m-chromosomes were present in the complement. Male meiotic prophase was characterized by a prominent condensation stage. At this stage, the sex chromosomes were positi...

A critical DNA damage checkpoint in Saccharomyces cerevisiae is an arrest at the metaphase stage of mitosis. Here we show that the S-phase cyclins Clb5 and Clb6 are required for this arrest. Strains lacking Clb5 and Clb6 are hypersensitive to DNA damage. Furthermore, in the presence of the DNA alkylating agent methyl methanesulfonate (MMS) over 50% of clb5 clb6 mutants by-passed the metaphase c...

The requisite endpoint of mammalian oocyte maturation, whether in vivo or in vitro, is a metaphase II oocyte which is able to be fertilized and which can eventually support normal embryonic development. Oocytes which have been matured in vivo basically fulfill these criteria. On the other hand, a completely different situation exists when these cells are isolated from the ovaries and cultured i...

The fragments of DNA attached to protein skeleton of interphase nuclei or metaphase chromosomes were obtained. Both the method involving restriction endonuclease treatment /1,2/ and a novel procedure based on mild staphylococcal nuclease digestion were used. In the latter case, DNA fragments remaining bound to nuclei or chromosomes are not enriched in satellite but only in abundant middle repet...

Because of the large number of cells to be analyzed in cases of overexposure to ionizing radiation, an automated imaging system is desirable for scoring both translocations and dicentrics. This system should include three essential steps: automatic metaphase finding, automatic image capture at high magnification, and, finally, optimized data analysis for aberration interpretation. We evaluated ...

In this paper is reported the development of a neural network (NN) based workstation for automated cell proliferation analysis, of cytological microscope images. The software of the system assists the expert biotechnologist during cell proliferation and chromosome aberration studies by automatically identifying metaphase spreads and stimulated nuclei on each digital image. After manual edition ...